Efficient synthesis of recyclable porous BiFeO3/rGO thin film via sol-gel method as an enhanced photocatalyst

This paper outlines the creation of BiFeO3-reduced graphene oxide (BrGO) thin films through a straightforward in-situ sol-gel method, followed by dip-coating and subsequent heat treatment. The resulting thin films exhibit high efficiency and reusability. Modifying the content of reduced graphene oxide (rGO) resulted in an exceptional porous morphology featuring a perovskite structure in a single phase. Due to in-situ synthesis, BiFeO3 (BFO) nanoparticles were grafted on rGO nanosheets and formed an intimate interface. Incorporating 5 wt% of rGO into the BFO composite led to a reduction in nanoparticle size range from 400 to 160 nm, an increase in film thickness from 220 to 375 nm, and an improvement in specific surface area from 4.13 to 34.69 m2.g−1. These alterations render the composite a viable choice for photocatalytic applications owing to its elevated active surface area. Also, adding rGO reduced the band gap energy from 2.4 to 2.2 eV, inhibiting the recombination of electron-hole pairs in comparison to BFO. Furthermore, the BrGO thin film exhibited increased photocurrent density, a consistent photocurrent response, and a reduced arc in the Nyquist plot. These observations validate an enhanced capability to generate, separate, and transfer photogenerated charges. The BrGO thin film exhibited exceptional photocatalytic efficacy, achieving nearly complete decomposition (96%) of organic dyes within 180 min under visible light. A comprehensive investigation into the photodegradation mechanism, considering energy band alignment and scavenger tests, revealed that holes and hydroxyl radicals are the most potent reactive species. The facile synthesis, elevated photocatalytic performance, and recyclability of the BrGO thin film position it as an optimal choice for widespread use in large-scale water purification applications.